1 68 THE TEACHING BOTANIST 



7. a. In a concise and tabular form, compare as to the 

 chief resemblances and differences the four 

 kinds of seed you have studied, - - the Bean, 

 Horse-chestnut, Morning-glory, and Corn. 

 b. Construct a series of four diagrams, showing by 

 corresponding colors the relative development 

 of the equivalent parts in the four embryos. 

 (Place this series on the upper half of one page, 

 and leave the remainder for a related series 

 to come later.) 



Materials. The Horse-chestnuts should be soaked for a 

 week ; if then the cotyledons do not separate readily, immer- 

 sion in hot (not boiling) water for a few minutes will make 

 them. For the purposes of this exercise it is a most valuable 

 seed, and every effort should be made to obtain it. Morning- 

 glory seeds, the largest size, which may be bought cheaply by 

 the ounce in seed stores, should be soaked only four hours. 

 Though this seed is small, it is hard to find a larger one which 

 is as instructive. The Castor Bean (Ricinus} germinates badly, 

 and hence cannot be followed into its later stages, while Four- 

 o-clock is puzzling through presence of the fruit. A lens will 

 make the Morning-glory sufficiently clear. Corn, soaked over 

 night, must be studied chiefly by sections. 



Pedagogics. - - This outline will require at least three two- 

 hour periods, with some outside work. 



Its object is to continue training in observation, and to form 

 an introduction to morphology. As to observation, after their 

 previous experience, the students will readily find in the Horse- 

 chestnut everything on the seed-coats, including the fibre-vas- 

 cular bundles on the hilum. The coats are two united, but 



